Another high-octane case against a media outlet is getting underway — this one, across the pond in the UK.

Both Prince Harry and Elton John were in court on Monday as proceedings commenced in an explosive lawsuit brought against Daily Mail publisher, Associated Newspapers.

The lawsuit, which was filed last year, alleges that Associated Newspapers was responsible for “abhorrent criminal activity and gross breaches of privacy” in its efforts to obtain dirt on celebrities. Allegations in the lawsuit include the placing of listening devices in victims’ homes and cars, bugging phone calls, and paying police for information.

Actresses Sadie Frost and Elizabeth Hurley, filmmaker David Furnish, and Doreen Lawrence, whose son was killed in a racist attack in 1997, are among the half-dozen high-profile figures joining together in the legal action.

The suit is just one of three that the Duke of Sussex has brought against major UK newspaper publishers, including Rupert Murdoch’s News Group Newspapers and Mirror Group Newspapers.

To be clear, Associated Newspapers has strongly denied the claims against it. When the lawsuit was filed, the publisher called the claims “preposterous smears” and it said it “utterly and unambiguously refuted” them.

Now it will be up to a judge from London’s High Court to determine whether the case will advance, or be thrown out as Associated Papers has motioned for.

Monday was the first in four days of pre-trial hearings, which are expected to conclude on Thursday, in which the judge will hear arguments ahead of rendering a decision.

The presence of Prince Harry and Elton John, which was done entirely on their own volition and not legally required, fueled media coverage on Monday, turning the press’ eye on the preliminary hearing. Their appearances were the top stories on a number of UK news websites. Even the Daily Mail published an article on their arrival in court.

A spokesperson for Prince Harry told Reuters that the Duke of Sussex wanted to be present to signal public support for the case. In other words, he attended to shine a spotlight on the case.

It’s no surprise that Prince Harry would use his celebrity to gin up attention about the lawsuit. He has spent years critiquing tabloid media and talked openly about the negative effects some of the coverage has had on his family.

As the barrister in the case said Monday, Harry “regards Associated’s unlawful acts to amount to a major betrayal given promises made by the media to improve its conduct following the tragic and untimely death of his mother, Princess Diana, in 1997.”

The allegations in the legal action are all eerily reminiscent of the behavior that was exposed in the News of the World scandal, which ultimately resulted in Murdoch shuttering the popular newspaper and the UK launching a probe into press ethics.

It’s unclear whether this case will result in such profound consequence. But if it does go to trial, it is safe to say that it will be precisely the type of trial that an outlet like the Daily Mail relishes in covering.